PHA granule binding protein phasin (PhaP) has a high affinity for hydrophobic materials and can bind to hydrophobic polymers via strong hydrophobic interaction. In this study, an EGFR-targeting peptide (ETP) was fused with PhaP and the fusion protein ETP-PhaP was produced in recombinant Escherichia coli BL21 (DE3) (pPI-ETP-P) and then purified by Ni affinity purification. The tumor targeting PHBHHx nanoparticles were developed based on PhaP mediated ETP immobilization and the cellular uptake of the ETP-PhaP modified PHBHHx NPs and none modified PHBHHx NPs by cervical cancer cell lines SiHa (EGFR over expressed) and CaSKi (EGFR low expressed) were analyzed. The purified ETP-PhaP could be adsorbed onto the hydrophobic surface of PHBHHx NPs. The ETP-PhaP modified PHBHHx NPs could target to EGFR over expressed cervical cancer cells SiHa more efficiently than to the EGFR low expressed CaSKi cells. These results demonstrated the advantage in effectiveness and convenience of PhaP mediated ETP adsorption on PHBHHx nanoparticles, providing a novel strategy for hydrophobic nanocarrier surface modification.
聚羟基脂肪酸 (PHA) 颗粒表面结合蛋白PhaP 具有与疏水性高分子材料表面紧密结合的能力，本研究将EGFR 靶向多肽 (ETP) 与PhaP 进行融合表达，构建了ETP-PhaP 融合蛋白表达的重组工程菌Escherichia coli BL21(DE3)(pPI-ETP-P)。经对工程菌株的诱导表达及ETP-PhaP 融合蛋白的纯化后，通过PhaP 蛋白介导能够有效地将ETP-PhaP 融合蛋白修饰于3-羟基丁酸-3-羟基己酸共聚酯 (PHBHHx) 纳米微球表面，构建成为具有EGFR 靶向作用的药物递送载体。分别检测宫颈癌细胞系SiHa(EGFR 高表达) 和CaSKi(EGFR 低表达) 对ETP-PhaP 修饰的PHBHHx 纳米药物载体和未经修饰的纳米药物载体的吞噬情况。结果显示，纯化的ETP-PhaP融合蛋白能够很好地吸附于PHBHHx 颗粒的表面，经ETP-PhaP 融合蛋白修饰的PHBHHx 纳米药物载体对EGFR 高表达的宫颈癌SiHa 细胞的靶向效果强于EGFR 低表达的CaSKi 细胞系。这一结果表明了PhaP 介导的PHBHHx 纳米微球表面EGFR 靶向多肽修饰具有简便、高效的优势，为疏水性纳米药物载体表面功能多肽修饰提供了一种新策略。.
Keywords: EGFR; PHBHHx; PhaP; drug delivery carrier; tumor targeting.